This invention relates to a method and a device for positioning a car body at a predetermined position on a transporting path in a manufacturing line.
Conventionally, a manufacturing line for a car body comprises a pressing station for pressing a steel plate into predetermined shape, a weld assembling station for subsequently joining the pressed parts, and a painting station for painting the assembled body. In particular, in the weld assembling station, a plurality of pressed parts are successively selected and are joined together in a predetermined order. The selected parts are transported to a predetermined joining station, where they are automatically joined using a predetermined weld processing machine. In such a manufacturing line, the body in the course of the assembling cycle is transferred by a conveyer to the subsequent weld processing station after completion of one welding process.
In general, for the aforementioned body manufacturing line, a shuttle conveyer is preferably applied which can rapidly transport the body in the course of the assembling cycle from a first conveyer to a subsequent weld processing station with high positioning accuracy.
The shuttle conveyer which acts as a second conveyer is widely used because it enables the implementation, at a relatively fast transportation speed, of a cycle for lifting, transporting, lowering and returning to an initial position with no parts thereon, a shuttle extending along the transporting direction. In the case where the body is transported by using this shuttle conveyer, a body which has already arrived at one transfer position is first positioned at a predetermined position. Subsequently, a projection on an upper surface of the shuttle is inserted into a predetermined engaging hole provided on a lower wall of the body to lift up the body. Thereafter, the shuttle is transported at high speed for one transportation distance. The shuttle is then lowered and transported to an initial transfer position with no parts thereon. It is noted that the positioning can be readily achieved, as the shuttle is lowered, with the engaging hole or the like disposed at a predetermined position on the lower wall of the body being engaged with an engaging member for use at restricting the position in the subsequent station, e.g., the welding station.
As mentioned above, when the body is transferred from the first conveyer to the second conveyer, it is necessary to accurately position the body at the transfer position.
Thus, in the transporting path for transporting a body using the conveyer, the body must be positioned depending on the necessity for an exchange on the transporting path. Accordingly, a positioning device is disposed on the transporting path of this kind.
When only one type of body is transported along the body manufacturing line, the lateral position can be restricted by using lateral position restricting guides which are securely arranged on each side of the transporting path. Further, the longitudinal positioning of the body can be carried out by means of a stopper member secured at the transfer position on the transporting path.